A conventional service provision system, as illustrated in FIG. 29, includes a load balancer 602, a switch 604 connected to the load balancer 602, and plural server devices 606 to 612 connected to the switch 604, each connected to a network 620. Server devices are referred to below as servers.
Each of the plural servers 606 to 612 are managed by a server provider (tenant provider side). The server provider provides a service provider (tenant usage side) intending to provide a service using servers with the number of individual servers designated by the service provider. For example, take the case in which a service provider has requested the server provider to provide two servers for providing a given service. The server provider selects two servers from out of the plural servers 606 to 612, and records the IP addresses of the selected two servers in the load balancer 602. When plural execution requests for a service that transmits home page data are received, for example, the load balancer 602 allocates each of the plural received requests to the two servers corresponding to the two recorded IP addresses. For example, the two IP addresses are, say, 001 and 111, and the IP address=001 corresponds to the server 606, and the IP address=111 corresponds to the server 612.
The load balancer 602 allocates each of the plural requests to either the IP address=001, or the IP address=111. The requests that have been allocated to either the IP address=001 or the IP address=111 are then allocated to either the server 606 or the server 612 through the switch 604. The server 606 and the server 612 transmit the home page data according to the allocated requests.
A configuration in which the same processing is executed on plural servers is referred to as a redundant configuration. Due to the processing being executed on the plural redundant servers in this manner, even if one of the plural redundant servers breaks down, the processing still continues on the remaining servers. This thereby enables the service outage percentage to be reduced.
A server provider performs maintenance on the servers so that the servers provided to the service provider do not break down. In the above example, since the server 606 and the server 612 are made redundant, even if the server 606 is shut down to perform maintenance on the server 606, the processing still continues on the remaining server 612. This thereby enables redundancy to be built into the plural servers, such that server maintenance can be performed without causing significant disruption to the business of the service provider.